In known weaving machines, every heald shaft or heddle of such machine is moved by a pair of lever elements, wherein these lever elements engage the respective heald shafts in the proximity of the two lateral ends thereof. The two lever elements belonging to a heald shaft are in that case connected by transmission elements in such a manner, that they both perforce execute the same motion and exert a pulling or pushing force on the heald shaft parallel to the healds. This construction is however relatively expensive because of the transmission elements necessary for the simultaneous movement of the two lever elements.
There is further already known a web machine with several heald shafts arranged one behind the other, in which only a single lever engages with each heald shaft. In this construction, the pivot axes of the lever elements extend perpendicularly to the healds but parallel to the general planes of the respective heald shaft assembly. Since the lever elements in such a known arrangement are arranged next to one another, they cannot all engage with the heald shafts in the middle thereof. This has the consequence, that the lever elements generate turning moments with respect to the centres of the respective heald shaft assemblies, whereby excessive loading of the lateral guides of the heald shafts may arise. This causes, particularly at great weaving speeds, on the one hand excessive wear of such guides and on the other hand the generation of excessive noise.